1. Field of the Invention
This invention relates to a key and a locking device to be operated by the key.
2. Description of the Related Art
As a key for locking or unlocking a locking device such as a cylinder lock, a key plate is used that has a plate body which is shaped like a plate and has an inside groove formed inside a plane thereof. The inside groove type key plate is used such that, by inserting the key plate into a key hole formed on a front surface of a rotor of the cylinder lock, plural tumblers formed in the rotor are engaged with end surfaces of the inside groove, and, when the key plate inserted is a regular key (or authentic key) of the cylinder lock, the tumblers are all drawn from an outer periphery of the rotor to allow the rotation of the rotor (e.g., JP-A-2005-344305).
According to the conventional key and locking device, a key family that has, e.g., ten tumblers, and the inside groove of the key at the position of each tumbler is set to be formed into three steps of a, b and c can have different key patterns of 310 in theoretical combination.